The present invention concerns an elevator having an optical system for initiating or triggering a function, such as a call for an elevator cabin.
In some elevator installations optical fibers are used to transmit information from a machine room control unit to an elevator display device, but these optical fibers have not fully replaced the electrical wiring and power lines required for power supply purposes and for signal transmission. The electrical supply is for example required to drive electronic information processing circuits and devices at the elevator landing area sites. In addition, certain elements at the elevator landing area sites and/or inside the elevator cabin require an electrical power supply. In consequence, the installation of these types of elevator installations is tedious, costly and error prone.
An example of an elevator with fiber-based optical information and power transmission is described in U.S. Pat. No. 4,623,869. In this patent, light pulses are transmitted via an optical fiber to a boarding area site where they are converted into electrical energy by means of a photoelectric transducer. Information is transmitted via the same fiber in the form of different pulses. These pulses are forwarded to a beam deflection unit which projects the optical information onto a viewing screen. The beam deflection unit is electro-mechanically operated, that is, it requires electrically powered devices. According to this US patent, electrical energy is converted into optical energy before it is transmitted through the fiber. At the receiving end, the optical energy is converted back into electrical energy, or electrical energy is required to mechanically deflect the optical beam onto the viewing screen. Such a hybrid approach is complex and expensive.
There are other examples of elevator installations that require a conversion from electrical into optical energy and at the receiving end a conversion back into electrical energy. One example is given in the Japanese patent application JP2002348067A.
Yet another approach is addressed in the Japanese patent application JP2002062387A. This Japanese patent application discloses an elevator where a button is illuminated by a lamp that is spaced apart from the button in order to prevent the lamp from being destroyed by vibrations inside the button. The lamp is connected to the button by means of an optical fiber.
All systems and approaches known so far are hybrid systems, where conversions from an electrical to an optical regime and from the optical to the electrical regime are required.
Conventional systems use too much space and are interference prone. Depending on the implementation, special communication protocols are required for communication between the control unit in the elevator's machine room and the panels on the different landing floors. Traveling direction devices and other indicators have the same problem.